package com.google.gwt.sample.dynatablerf.server.filters;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.google.gwt.sample.dynatablerf.shared.GrifoSharedConstants;

public class TimeoutFilter implements Filter {
    
    public void init(FilterConfig filterConfig) throws ServletException {}
    public void destroy() {}

    public void doFilter(ServletRequest request, ServletResponse response,
        FilterChain filterChain) throws ServletException, IOException {
        if ((request instanceof HttpServletRequest) &&
            (response instanceof HttpServletResponse)) {
            HttpServletRequest httpServletRequest = (HttpServletRequest) request;
            if (!isValidSession(httpServletRequest)) {
                throw new ServletException(GrifoSharedConstants.TIMEOUT_EXCEPTION_CODE);
            }
            filterChain.doFilter(request, response);
        }
    }

    private boolean isValidSession(HttpServletRequest httpServletRequest) {
        return (httpServletRequest.getRequestedSessionId() != null) &&
               httpServletRequest.isRequestedSessionIdValid();
    }
}
